Theophrastus is considered the father of botany; he proposed an artificial classification of plants on the basis of their morphological features into tree, shrubs, sub-shrubs and herbs.
John Ray classified plants into Herbae (herb) and Arborae (tree and shrubs), based on their habits. These groups were then divided into flower less and flowering plants; the flowering plants were further classified on the basis of a number of cotyledons.
Bentham and Hooker proposed the most elaborate natural classification of seed plants in their three-volume book “Genera Plantarum”.
Linnaeus is considered the father of taxonomy; he gave artificial and sexual classification of plants and identified 24 classes of flowering plants based on the number of stamens and their adnate or connate state. The last class was termed as “Cryptogamia” in which he placed all non-flowering plants (algae, fungi, lichen, mosses and fern).